Aim

One of the most important ways to understand the ovarian biology is studding the initiation of primordial follicle development and subsequent folliculogenesis control. In this study, proliferating cell nuclear antigen (PCNA) presentation was used as a marker of follicular development in the thawed ovarian tissue (OT) following transplantation onto chick embryo chorioallantoic membrane (CAM) using two methods of freezing of slow freezing and vitrification.

Methods

Samples of OT from 10 patients were subjected to slow freezing and vitrification. After warming, CAM transplantation was done and PCNA proliferation index (PI; percent of PCNA-positive granulosa cells) was calculated for each follicle stage. Image J software was used to determine the mean staining intensity.

Results

PCNA was positive for granulosa cells and oocytes nuclei, but negative for ooplasm. There were no remarkable PCNA staining in the granulosa cells of primordial follicles, but increased significantly as follicle progression (p < 0.05). Proliferation rate was also insignificantly higher in the vitrified than slow freezing group, before and after transplantation (p < 0.05). Lower PCNA presentation index was observed after CAM transplantation (p < 0.05). The earliest stage of follicular recruitment took place in the transitional follicles, before squamous cells transform to cuboidal cells.

Conclusion

PCNA showed that follicles had proliferation power after cryopreservation. Higher presentation after vitrification may indicate accelerated folliculogenesis in the thawed OT.